CN110958857B - Ultrasound diagnostic equipment - Google Patents

Abstract

Provided is an ultrasonic diagnostic apparatus, wherein the drive current of a vibrator is constant relative to semiconductor process variation. An ultrasonic diagnostic apparatus includes an oscillator, a drive signal generating unit configured to generate a drive signal, and a transmission circuit configured to output a drive current corresponding to the drive signal and drive the oscillator, wherein the transmission circuit includes an oscillator driving unit including a low-voltage transistor and a high-voltage transistor and connected to the oscillator, and a current source configured to supply an operation current corresponding to the drive signal to the low-voltage transistor of the oscillator driving unit, the drive signal generating unit includes a transmission circuit driving unit having the same configuration as the oscillator driving unit and a feedback control unit configured to detect a current flowing to the high-voltage transistor of the transmission circuit driving unit and control the current to be constant, and a signal applied from the feedback control unit to the current source configured to supply the operation current to the low-voltage transistor of the transmission circuit driving unit is supplied as the drive signal to the oscillator driving unit The low-voltage transistor supplies a current source of an operating current.

Description

Ultrasound diagnostic equipment

technical field

The present invention relates to an ultrasonic diagnostic apparatus.

Background technique

In an ultrasonic diagnostic apparatus, there is an imaging method called tissue harmonic imaging (THI) that visualizes the distortion components generated in the living body. Compared with the normal brightness (Brightness, B) mode imaging, By utilizing the harmonic components, it is possible to reduce the influence of side lobes, artifacts, etc. generated in the fundamental wave, and to achieve higher image quality. In THI, there are two methods: a filter method in which only secondary distortion components generated in a living body are extracted using a filter, and an impulse inversion method in which a fundamental wave component is removed by adding positive and negative symmetrical waves. The filter method can perform imaging by transmitting and receiving once, but it is necessary to separate the fundamental wave component and the harmonic component, so a narrow-band transmission waveform is required, and the spatial resolution is lowered. On the other hand, the pulse inversion method requires transmission and reception twice during imaging, but does not require separation of fundamental wave components and harmonic components, so it is known that wide-band transmission can be achieved and spatial resolution can be improved. In recent ultrasonic waves Among diagnostic apparatuses, THI using the pulse inversion method has gradually become the mainstream.

prior art literature

Patent Literature

Patent Document 1: International Publication No. 2016/114018

SUMMARY OF THE INVENTION

The problem to be solved by the invention

In THI using the pulse inversion method, it is the positive and negative symmetry of the transmitted waveform that is important. Since the positive and negative transmission and reception signals are added, if the rise and fall of the transmission waveform are different, cancellation residues occur after the addition, resulting in image degradation. In particular, in a pulse transmission circuit that generates high/low discrete signals, it is known that positive and negative asymmetry is formed due to semiconductor process variations because PMOS transistors and NMOS transistors having different transistor polarities are used to generate discrete signals.

Patent Document 1 describes a technique in which a replica of the same structure is prepared for a transmission circuit drive unit composed of a low-voltage transistor and a high-voltage transistor, and the sum of the currents flowing therethrough is made constant, thereby reducing the process variation with respect to the process. , so that the drive current is constant. However, in Patent Document 1, although the sum of the currents of the low-voltage transistors and the high-voltage transistors in the replica part is constant, the current ratio (mirror ratio) flowing to the low-voltage transistors and the high-voltage transistors fluctuates due to variations in the semiconductor process. Therefore, the current flowing to the high-voltage transistor of the transmission circuit drive unit, that is, the drive current cannot be constant, and it is difficult to form a positive-negative symmetrical waveform with high accuracy.

In view of this, an object of the present invention is to provide an ultrasonic diagnostic apparatus in which the drive current of the transducer is constant with respect to semiconductor process variations.

means of solving problems

An example of an "ultrasonic diagnostic apparatus" of the present invention for solving the above-mentioned problems is an ultrasonic diagnostic apparatus including a vibrator, a drive signal generator that generates a drive signal, and a drive that outputs a drive corresponding to the drive signal. A transmission circuit that drives the vibrator with current, the transmission circuit is composed of a vibrator drive part and a current source, the vibrator drive part is composed of a current mirror of a low-voltage transistor and a high-voltage transistor, and the high-voltage transistor is connected to the vibrator The current source supplies an operating current corresponding to the drive signal to the low-voltage transistor of the vibrator drive unit, and the drive signal generation unit includes a transmission circuit drive unit replica that is the same as the vibrator drive unit structure; and a feedback control unit that detects a current flowing to a high-voltage transistor of the transmission circuit drive unit replica, controls the current to be constant, and applies the current to the transmission circuit drive unit from the feedback control unit The signal of the current source that supplies the operating current to the low-voltage transistor of the replica is supplied as the drive signal to the current source that supplies the operating current to the low-voltage transistor of the vibrator driving unit.

Invention effect

According to the present invention, the drive current of the vibrator can be kept constant with respect to semiconductor process variations.

Problems, structures, and effects other than those described above will become clear from the description of the following embodiments.

Description of drawings

FIG. 1 is a block configuration diagram of a drive signal generation unit and a transmission circuit according to Embodiment 1 of the present invention.

FIG. 2 is an example of a detailed circuit diagram of FIG. 1 .

FIG. 3 is a diagram showing control signals and transmission waveforms of the transmission circuit of FIG. 1 .

4 is a diagram showing a configuration example of the ultrasonic diagnostic apparatus according to the first embodiment.

5 is a block configuration diagram of a drive signal generation unit and a transmission circuit according to Embodiment 2 of the present invention.

FIG. 6 is an example of a detailed circuit diagram of FIG. 5 .

FIG. 7 is a diagram showing control signals and transmission waveforms of the transmission circuit of FIG. 5 .

FIG. 8( a ) is a diagram showing a pulse-inverted transmission waveform and residual components when there is no drive signal generating unit, and FIG. 8( b ) is a graph showing a case where a drive signal generating unit is provided A graph of the pulse-inverted transmit waveform and residual components.

9 is a diagram showing a configuration example of an ultrasonic diagnostic apparatus according to Embodiment 3 of the present invention.

10 is a diagram showing a configuration example of an ultrasonic diagnostic apparatus according to Embodiment 4 of the present invention.

FIG. 11 is a diagram showing a configuration example of the transmission circuit of FIG. 10 .

FIG. 12 is a diagram showing a configuration example of an ultrasonic diagnostic apparatus according to Embodiment 5 of the present invention.

FIG. 13 is a diagram showing an operation mode and power consumption of the ultrasonic diagnostic apparatus of FIG. 12 .

Detailed ways

In the following embodiments, the description is divided into a plurality of parts or embodiments when necessary for convenience, but unless otherwise specified, they are not unrelated to each other, and one of them is a part of the other. or all modifications, details, supplementary explanations, etc. In addition, in the following embodiments, when referring to the number of elements, etc. (including the number, numerical value, amount, range, etc.) In addition, it is not limited to this specific number, The specific number or more may be sufficient as it, and a specific number or less may be sufficient as it.

In addition, in the following embodiments, the constituent elements (including element steps and the like) are of course not necessarily essential except for the case where it is expressly specified or the case where it is clearly considered essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc. of the constituent elements, unless it is specifically stated or it is clearly considered to be necessary in principle, it includes a substantially similar shape or the like or the like. similar situations etc. The same applies to the above-mentioned numerical values and ranges.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In addition, in all the drawings for describing an embodiment, the same code|symbol is attached|subjected to the same member in principle, and the repeated description is abbreviate|omitted.

Ultrasound diagnostic apparatuses are widely used as medical diagnostic apparatuses capable of non-invasive and real-time observation. In addition, in recent years, in addition to the conventional two-dimensional images, three-dimensional stereoscopic images and the like can be displayed, and the use thereof has been expanding. On the other hand, with regard to image quality, when compared with X-ray CT (Computed Tomography) apparatuses and MRI (Magnetic Resonance Imaging) apparatuses, the resolution is low, and therefore, increased high-resolution images have also been demanded in the past. qualitative. Hereinafter, an example in which the present invention is applied to an ultrasonic diagnostic apparatus will be described.

Example 1

FIG. 1 is a block diagram showing a drive signal generation unit and a transmission circuit according to Embodiment 1 of the present invention. The drive unit 7 inside the transmission circuit 102 that drives the vibrator 8 outputs a drive current corresponding to the drive signal supplied from the drive signal generation unit 9 to drive the vibrator 8 . At this time, a control signal is input to the transmission circuit 102, and the drive signal is enabled or disabled by the control signal, whereby a drive current flows to the output, and High and Low signals can be generated.

The drive signal generation unit 9 includes a reference voltage generation unit 1 , a difference detection unit 2 , a voltage-to-current conversion unit 3 , a transmission circuit driving unit replica 4 , a current detection unit 5 , and a current-to-voltage conversion unit 6 . The difference detection unit 2 , the voltage-to-current conversion unit 3 , the transmission circuit driving unit replica 4 , the current detection unit 5 , and the current-to-voltage conversion unit 6 constitute a feedback control unit, and the output voltage of the difference detection unit 2 is converted into a voltage-current conversion unit 3 . The current is transmitted to the replica 4 of the transmission circuit driver. In the transmission circuit drive unit replica 4 , a drive current is generated similarly to the transmission circuit drive unit 7 , passed through the current detection unit 5 , converted into a voltage signal by the current-voltage conversion unit 6 again, and returned to the difference detection unit 2 . At this time, due to the feedback effect, a voltage equal to the reference voltage is finally input to the input of the difference detection unit 2 . That is, it means that the output voltage of the current-voltage converting unit 6 is equal to the reference voltage of the reference voltage generating unit 1 . The current flowing to the current-voltage converting unit 6 is the driving current transmitted from the current detecting unit 5, and therefore, the driving current becomes a constant value. The current for generating the drive current is the output current of the voltage-current converter 3, and by inputting this current as a drive signal to the transmission circuit 102, the drive current output from the transmission circuit 102 can be kept constant.

FIG. 2 shows a specific configuration example. The transmission circuit 102 includes an NMOS transistor 19 that converts a drive signal into a current, a switch 18 that enables and disables the drive signal by a control signal, a drive unit 7 , and a load resistor 20 . The drive unit 7 is constituted by a current mirror as a high-voltage NMOS transistor 15 , a low-voltage PMOS transistor 16 , and a high-voltage PMOS transistor 17 that are level-shifted for NMOS transistor protection to apply a high-voltage power supply VDD1 . The NMOS transistor 19 that converts the drive signal into a current can be referred to as a current source that causes an operating current corresponding to the drive current to flow to the low-voltage PMOS transistor 16 .

Regarding the drive signal generation unit 9 , the reference voltage generation unit 1 is constituted by a resistor 10 and a current source 11 . The difference detection unit 2 is composed of the OPAMP 13 , and the output of the OPAMP 13 is connected to the voltage-current conversion unit 3 . The voltage-current converting unit 3 converts the output voltage from the OPAMP 13 into a current through the NMOS transistor 14 and inputs the current to the driving unit replica 4 . The drive current output from the drive unit replica 4 is output from the current detection unit 5 including the current mirrors of the NMOS transistors 21 and 22 . This current is converted into a voltage again by the resistor 12 serving as the current-voltage conversion unit 6 , and is input to the difference detection unit 2 . The NMOS transistor 14 can be referred to as a current source for flowing an operating current to the low-voltage PMOS transistor 16 of the transmission circuit driver replica 4 .

The detailed operation will be further described. The negative terminal of the OPAMP 13 is connected to one side of the resistor 10 connected to the current source 11 and the power supply VDD, and the positive terminal is connected to the one side terminal of the resistor 12 connected to the power supply VDD and the drain terminal of the NMOS transistor 22 of the current detection unit 5 . At this time, the voltage of the negative terminal of the OPAMP 13 is set to Vo, and in the initial state, the positive terminal of the OPAMP 13 becomes VDD when the current of the NMOS transistor 22 is zero. The output of the OPAMP 13 becomes High and the NMOS transistor 14 is turned on. Therefore, the current Ic is supplied from the drain terminal of the NMOS transistor 14 and is input to the drive unit replica 4 . I _DRIVE ′ is output from the output of the drive unit replica 4 and input to the current detection unit 5 . The NMOS transistors 21 and 22 of the current detection unit 5 are current mirrors with a mirror ratio of N:1, and apply a current of I _DRIVE ′/N from the drain terminal of the NMOS transistor 22 to the resistor 12 serving as the current-to-voltage conversion unit 6 . At this time, since a series of operations performs a negative feedback operation, the positive terminal and the negative terminal of the OPAMP 13 are automatically controlled to have the same potential. That is, the positive terminal of OPAMP13 becomes Vo. When the resistance values of the resistor 10 and the resistor 12 are equal, Ib equal to the current source 11 is supplied from the drain of the NMOS transistor 22 . Since the current mirror ratio of the NMOS transistor of the current detection unit 5 is N:1, I _DRIVE ′ is expressed as Equation (1).

[Formula 1]

I _DRIVE '=Ib/N (1)

At this time, when the mirror ratio of the low-voltage transistor 16 and the high-voltage transistor 17 of the drive unit replica 4 is M, the current supplied from the NMOS transistor 14 to the PMOS transistor 16 of the drive unit replica 4 is expressed as equation (2) .

[Formula 2]

Ic=I _DRIVE '/M=Ib/(N×M) (2)

In the NMOS transistor 19 of the transmission circuit 102, when the switch 18 is turned on, the same potential as that of the NMOS transistor 14 of the drive signal generation unit 9 is input to the gate terminal as a drive signal. Therefore, the same current as Ic input from the drain terminal of the NMOS transistor 14 to the drive unit replica 4 of the drive signal generation unit 9 is also input to the transmission circuit drive unit 7 . The transmission circuit drive unit 7 is also composed of the same low-voltage PMOS transistor 16 and high-voltage PMOS transistor 17 as the drive unit replica 4, so the mirror ratio becomes M and the I _DRIVE becomes Equation (3).

[Formula 3]

_IDRIVE =M×Ic=Ib/N (3)

That is, the drive current is determined only by the mirror ratio of the current value Ib of the current source 11 and the current detection unit 5, even if the mirror image of the low-voltage PMOS transistor 16 and the high-voltage PMOS transistor 17 of the drive unit 4 is duplicated due to process variation or the like As the ratio M varies, the drive current I _DRIVE is also constant.

At this time, the driving unit replica 4 and the driving unit 7 are supplied with the same power supply VDD1, and have the high-voltage NMOS transistor 15, whereby a high voltage can be applied, and therefore, variation due to the voltage dependence of the driving voltage can be suppressed. .

The drive current can be adjusted by changing the mirror ratio N of the NMOS transistors 21 and 22 or the current value Ib of the current source 11 , but the resistance ratio of the resistor 12 and the resistor 10 can also be adjusted.

FIG. 3 shows the control operation of this embodiment. The control signal is a signal input to the switch 18. In Low (L), the switch is turned off, and the gate terminal of the NMOS transistor 19 becomes GND. In High (H), the switch is turned on, and the gate terminal is connected to the slave driver. The driving voltage output from the signal generating unit 9 is connected. The NMOS transistor 19 connected to the drive voltage outputs the drive current I _DRIVE from the high-voltage PMOS transistor 17 of the drive unit 7 and applies it to the load resistor 20 and the vibrator 8 . Most of the drive current flows to the vibrator 8 . The output voltage Vout rises with the application of the drive current, and when it rises to the vicinity of VDD1, the high-voltage PMOS transistor 17 of the drive unit 7 becomes a linear region, and therefore, only current is supplied to the load resistance. On the other hand, when the control signal becomes L, Ic becomes zero, and the drive current I _DRIVE becomes zero. Therefore, the electric charge charged to the vibrator 8 is discharged by the load resistor 20, and the output voltage becomes zero. Thereby, an ultrasonic transmission signal can be generated. In this embodiment, the drive current I _DRIVE output from the high-voltage PMOS transistor 17 is constant, and therefore, the slope of the output voltage Vout is constant.

FIG. 4 shows a configuration example in which the drive signal generation unit 9 and the transmission circuit 102 of the present embodiment are applied to the ultrasonic diagnostic apparatus 300 . The drive signal control signal from the control unit 101 is transmitted to the drive signal generation unit 9, and the drive signal value is determined. The transmission control signal is transmitted to the transmission circuit 102, and the transmission signal is formed by turning on and off the switch. The transmission signal output from the transmission circuit 102 is converted into an ultrasonic signal by the ultrasonic transducer 103 and irradiated to the living body. The reflected signal from the living body is received again by the ultrasonic transducer 103 , converted into an electrical signal, signal-processed by the transceiver separation unit 104 , the receiving circuit 105 , and the image processing unit 106 , and displayed as an ultrasonic image by the display unit 103 . At this time, the transmission circuit 102 , the transmission/reception separation unit 104 , and the reception circuit 105 are arranged in the same number as the plurality of ultrasonic transducers 103 . Only one drive signal generation unit 9 may be provided in common with the plurality of transmission circuits 102 . The plurality of transmission circuits 102 and the drive signal generation unit 9 may be formed on the same semiconductor.

Low-voltage transistors and high-voltage transistors vary greatly depending on the semiconductor manufacturing process, but according to the present embodiment, it is possible to provide an ultrasonic diagnostic apparatus in which the driving current of the ultrasonic transducer is constant with respect to the semiconductor process fluctuations of the low-voltage transistor and the high-voltage transistor .

Example 2

FIG. 5 shows Embodiment 2 of the present invention. In the second embodiment, the positive and negative driving current can be supplied to the vibrator 8 . The transmission circuit 102 includes a positive-side driver 7a and a negative-side driver 7b, and inputs a positive power supply VDD1, a control signal a, and a driving signal a to the positive-side driver 7a, and inputs a negative power supply VDD2 and a control signal to the negative-side driver 7b b and the drive signal b. The drive signals a and b are generated by the drive signal generating units 9a and 9b, respectively. The outputs of the drive units 7 a and 7 b of the transmission circuit 102 are connected to the vibrator 8 .

FIG. 6 is an internal configuration diagram of FIG. 5 . The driving signal generating unit 9a and the positive side driving unit 7a for generating the positive side driving signal a have been described in the first embodiment. The drive signal generation unit 9b that generates the negative-side drive signal b automatically adjusts the current flowing from the PMOS transistor 31 to the resistor 23 by feedback control so that, as in the first embodiment, at the negative terminal of the difference detection unit 2b, the current source 33 The reference current Ib of , and the reference voltage Vob generated by the resistor 34 have the same potential. When the resistor 34 and the resistor 23 are equal, the current flowing to the resistor 23 becomes Ib, and when the current mirror ratio of the negative-side current detection unit 5b is set to 1:N, the high-voltage NMOS transistor of the negative-side transmission circuit replica unit 4b is sent to the negative side. The current flowing at 28 becomes Ib/N. When the current mirror ratio between the low-voltage NMOS transistor 27 and the high-voltage NMOS transistor 28 of the negative-side transmission circuit replica portion 4b is set to Mb, Ib/(N×Mb) flows to the drain of the low-voltage NMOS transistor 27, and the positive Similarly, since the gate potential of the PMOS transistor 25 that causes the current to flow becomes the drive signal b, the drive current I _DRIVE2 of Ib/N flows to the negative-side drive unit 7 b of the transmission circuit 102 . This drive current is the same as that on the positive side, and is determined by the current mirror ratio N of the PMOS transistors 31 and 32, and is therefore not affected by process variations of the semiconductor.

Next, the operation of FIG. 6 will be described with reference to FIG. 7 . The driving currents I _DRIVE1 and I _DRIVE2 are caused to flow by the activation and deactivation of the control signal, which is the same as the description of the first embodiment. The difference from Embodiment 1 is that it is possible to output three values of VDD1, VDD2, and zero. In FIG. 7(a), initially, the control signal a becomes High, and the output changes from zero to VDD1. Next, the control signal a becomes Low, and the control signal b becomes High. At this time, the output transitions from VDD1 to VDD2. After that, when both the control signal a and the control signal b become Low, the output becomes zero. In FIG. 7(b), the control signal a is opposite to the control signal b, and the output is also inverted. By alternately transmitting the symmetrical waveforms and adding the received waveforms, the fundamental wave component can be removed. It should be noted that, for example, VDD1 can be +50V, VDD2 can be -50V, and the current source 33 and VDD applied to the current detection unit 5b can be +5V.

FIG. 8 shows a conceptual diagram of pulse inversion. FIG. 8( a ) shows the residual components after adding the transmission waveforms when there is no drive signal generating unit and the positive-side drive current is smaller than the negative-side drive current due to variations in the semiconductor process. When the positive-side drive current decreases and the rise time is delayed, residual components remain, which leads to deterioration of the diagnostic image. On the other hand, when the drive current is generated by the drive signal generating units 9a and 9b in FIG. 5, the drive current becomes constant, and therefore, as shown in FIG. Residual components are present. As a result, it is possible to achieve higher image quality of ultrasonic images.

Example 3

FIG. 9 shows Embodiment 3 of the present invention. Embodiment 3 is an application example to the ultrasonic diagnostic apparatus of the present invention. The ultrasonic diagnostic apparatus 300 includes a main frame 201 , an ultrasonic probe 203 connected via a cable 202 , and an image display unit 107 . The ultrasonic transducer 103 is arranged in the ultrasonic probe 203 , and the transmission circuit 102 arranged inside the main frame 201 and the ultrasonic transducer 103 are connected via wiring inside the cable 202 . At this time, the transmission circuit 102 and the drive signal generation unit 9 are arranged inside the main frame 201 . A plurality of ultrasonic transducers 103 and transmission circuits 102 may be arranged.

Example 4

FIG. 10 shows Embodiment 4 of the present invention. Embodiment 4 is a second application example of the ultrasonic diagnostic apparatus of the present invention. The ultrasonic diagnostic apparatus 300 includes a main frame 201 , an ultrasonic probe 203 connected via a cable 202 , and an image display unit 107 . The ultrasonic transducer 103 , the transmission circuit 102 , and the drive signal generator 9 are arranged on the ultrasonic probe 203 .

At this time, the ultrasonic transducers 103 arranged in the ultrasonic probe 203 are arranged in an M×N two-dimensional array. As shown in FIG. 11 , by connecting the analog front-end circuits 41 to the ultrasonic transducers 103 , and adjusting the timing of transmission and reception, a three-dimensional ultrasonic image can be acquired. The analog front-end circuit 41 is configured to include a transmission circuit 102 and a reception circuit 105 corresponding to the ultrasonic transducer 103 , respectively. The M×N analog front-end circuits 41 are formed on the same semiconductor, and are integrated as a beamforming IC 40 together with a delay control unit and an amplitude voltage generation unit (not shown). At this time, as shown in FIG. 11 , the drive signal generation unit 9 is arranged outside the two-dimensional array of M×N analog front-end circuits 41 , and supplies the drive signal to the plurality of transmission circuits 102 in common. At this time, the driving signal may be sent to the integrated circuit in the form of wiring through the same wiring, or it may be converted into a current at one time, sent as a current, and then returned to the driving signal again and input to the transmission circuit 102 .

Example 5

FIG. 12 shows an ultrasonic diagnostic apparatus according to Embodiment 5 of the present invention. In the fifth embodiment, the operation of the drive signal generation unit 9 is synchronized with the operation of the transmission circuit 102 .

As shown in the operation diagram of FIG. 13 , in the ultrasonic diagnostic apparatus, an ultrasonic image is generated by alternately repeating a transmission section TX in which the transmission circuit is operated to transmit ultrasonic waves and a reception section RX in which reflected ultrasonic waves are received. In the present embodiment, an operation control signal for enabling and disabling the circuit is input to the drive signal generating unit 9 . The drive signal generation unit 9 operates (calibration operation) only when a valid operation control signal is input, and stops the operation when it is invalid. As shown in FIG. 13 , by synchronizing the calibration operation of the drive signal generation unit 9 with the operation of the transmission circuit 102 and setting the operation of the drive signal generation unit 9 only in the transmission interval TX, the average value of the drive signal generation unit 9 can be Power down, reducing power consumption.

Description of reference numbers:

1 reference voltage generation part;

2 Differential detection part;

3 Voltage and current conversion part;

4 A copy of the drive part of the sending circuit;

5 Current detection part;

6 Current-voltage conversion part;

7 Sending circuit driver;

8 vibrators;

9 driving signal generation part;

10, 12 resistance;

11 Constant current source

13 OPAMP;

14, 19 transistors;

15 high-voltage transistors;

16 low-voltage transistors;

17 high voltage transistor;

18 switches;

20 load resistance;

21, 22 transistors;

40 beamforming ICs;

41 analog front-end circuit;

101 Control Department;

102 sending circuit;

103 Ultrasonic vibrator;

104 transceiver separation part;

105 receiving circuit;

106 Image processing department;

107 Display part;

201 main frame;

202 cable;

203 Ultrasonic probe;

300 Ultrasound Diagnostic Units.

Claims (14)

1. An ultrasonic diagnostic apparatus is provided with: a vibrator; a drive signal generating unit for generating a drive signal; and a transmission circuit for outputting a drive current corresponding to the drive signal to drive the oscillator,

the transmission circuit is composed of an oscillator drive unit and a current source,

the vibrator driving unit is composed of a current mirror including a low-voltage transistor and a high-voltage transistor, the high-voltage transistor is connected to the vibrator,

the current source supplies an operating current corresponding to the drive signal to a low-voltage transistor of the oscillator drive unit,

the drive signal generation unit includes:

a transmission circuit driving unit replica having the same configuration as the oscillator driving unit; and

a feedback control section that detects a current flowing to the high-voltage transistor of the transmission circuit driving section replica and controls the current to be constant,

a signal applied from the feedback control unit to a current source that supplies an operating current to the low-voltage transistor of the transmitter circuit driving unit replica is supplied as the driving signal to a current source that supplies an operating current to the low-voltage transistor of the oscillator driving unit,

the feedback control unit is configured by:

a reference voltage generating unit that generates a reference voltage;

a current detection unit that detects a current flowing to the high-voltage transistor of the transmission circuit driving unit replica;

a current-voltage conversion unit that converts the current detected by the current detection unit into a voltage;

a difference detection unit that compares the reference voltage generated by the reference voltage generation unit with the voltage converted by the current-voltage conversion unit and detects a difference; and

a voltage-current conversion section that converts the difference into a current and supplies the current to the low-voltage transistor of the transmission circuit driving section replica.

2. The ultrasonic diagnostic apparatus according to claim 1,

the current source is configured by a transistor that changes the drive signal to a current, a switching means that enables and disables input of the drive signal by a control signal is provided at a gate terminal of the transistor, and a transmission signal is generated based on the drive signal and the control signal.

3. The ultrasonic diagnostic apparatus according to claim 1,

the same power supply voltage is applied to the current mirrors of the low-voltage transistor and the high-voltage transistor of the transmission circuit and the current mirrors of the low-voltage transistor and the high-voltage transistor of the transmission circuit driving section replica.

4. The ultrasonic diagnostic apparatus according to claim 3,

a high-voltage transistor is connected in series to each of the low-voltage transistor of the transmission circuit and the low-voltage transistor of the replica of the transmission circuit driving unit.

5. The ultrasonic diagnostic apparatus according to claim 1,

the drive signal generating section is provided in common to the plurality of transmission circuits.

6. The ultrasonic diagnostic apparatus according to claim 1,

the transmission circuit and the drive signal generation section are formed on the same semiconductor.

7. The ultrasonic diagnostic apparatus according to claim 1,

the vibrator driving unit is composed of a positive side driving unit composed of a PMOS transistor and a negative side driving unit composed of an NMOS transistor, and is capable of supplying different positive and negative driving currents to the vibrator,

the drive signal generating unit is arranged to make a drive current constant in each of the positive side drive unit and the negative side drive unit.

8. The ultrasonic diagnostic apparatus according to claim 7,

the vibrator driving unit supplies a driving current in which positive and negative are alternately inverted to the vibrator,

the transducers transmit alternately inverted ultrasonic waves.

9. The ultrasonic diagnostic apparatus according to claim 8,

by alternately transmitting symmetric waveforms of ultrasonic waves and adding received waveforms, fundamental wave components are removed.

10. The ultrasonic diagnostic apparatus according to claim 1,

the vibrator is arranged in the ultrasonic probe,

the transmission circuit and the drive signal generation unit are disposed in a main frame,

the ultrasonic probe is connected with the main frame through a cable.

11. The ultrasonic diagnostic apparatus according to claim 1,

the transducer, the transmission circuit, and the drive signal generating unit are disposed in an ultrasonic probe.

12. The ultrasonic diagnostic apparatus according to claim 11,

the ultrasonic diagnostic apparatus includes:

m × N vibrators formed in a two-dimensional array;

m × N analog front-end circuits corresponding to the respective oscillators and including transmission circuits; and

and a drive signal generating unit for supplying drive signals to the plurality of transmission circuits.

13. The ultrasonic diagnostic apparatus according to claim 12,

the M × N analog front-end circuits and the drive signal generating section are formed on the same semiconductor.

14. The ultrasonic diagnostic apparatus according to claim 1,

the calibration operation of the drive signal generation unit and the transmission operation of the transmission circuit are performed in synchronization, and the drive signal generation unit is operated only in a transmission section.

Images